Play for ten minutes and you're ready to write your review
The game can be played with two players which is always a plus, multi-player games are only good when it's optional and not forced like in Gyromite. When in multi-player you can climb mountains together and it really makes a difference when you play it with the right person (don't play it with your little sister, I had to learn that the hard way).
You can select which mountain you want to play (there is a total of 32 mountains available) on the same screen where you select with how many players you want to play, there is no code or trick you need to pull off in order to get there. I don't understand why so many games want you to enter a cheat-code or finish levels first before you may play them out of order, it's just something that seems pretty basic to me, especially when your game has a multi-player mode and the two of you don't want to do the easy levels first.
The game is fun to play which is probably the most important thing I can mention, it has flaws and some parts are just annoying, but it's just a lot of fun to play and has a high replay-value. I just love to guide my little blue guy to the top of a mountain, picking up carrots and hitting birds along the way and when we finally get there he just stands there and cheers while the game is dealing with the score. I also like how the game removed the time limit and doesn't punish you if you at least made it to the bonus stage, even if you die you just lose one of your lives and can continue without starting the stage all over.
You always jump or fall through platforms which is annoying, the platforms have really weird rules and combined with the way your character jumps (I'll tell more about that in the next paragraph) it makes for a lot of falling and dying in the later stages and bonus sections. Imagine if in Super Mario Bros. you would try to jump on a small platform, but instead you would just miss it and then go through it into the lava pit on the other side, it would look silly, but keep in mind that Mario jumps like normally.
When you jump in this game it's not like most games where you jump far, you jump high, which means you can try to jump over a small gap that shouldn't prove a challenge and still fall through it unto one of the enemies. It's not only flawed it also feels wrong to jump like this because I can't recall any other platforming game that used something similar. You'll get used to this eventually, but that's not really an excuse to design the game the way they did.
You can pretty much play the first few levels and then some of the later ones and you can write a review, no wait, scratch that, you can play the first few levels and then write a review, let me explain: The first few levels consist of small platforms, moving platforms and platforms that move you around, the only difference in the last few stages is the size of the small platforms and the speed of the moving platforms, nothing else changes. The music and the goals are always the same, there is just a small difficulty curve and nothing special aside from that.
The Bottom Line
Ice Climber is a game that's fun to play when you are bored for a while, but it's certainly no Legend of Zelda or Mega-man, you are just a sprite trying to climb a few mountains while avoiding other sprites and picking up some sprites during bonus rounds, it's not really an adventure as much as it is an arcade-game, like Donkey Kong and Pacman.
If you have a NES lying around and you don't have this game yet it could make a welcome addition to your collection, but it's definitively not a system-seller, it's just too simple and flawed to be the same as Super Mario Bros.